Bush drifted through his scheduled events this week with a surreal detachment, while the experts at Treasury and the Federal Reserve took charge of the crisis by dumping the full cost of the financial industry’s risky investments straight into the laps of the American taxpayer. The lifeline to Fannie Mae and Freddie Mac, the nationalization of AIG and the backing of $700 billion in bad mortgages may indeed save the economy, but it leaves Bush’s successor with no wiggle room in terms of spending.

The problems begin with the Bush tax cuts of 2001, which McCain and Obama both opposed at the time. In the 2008 primaries, McCain reversed himself on extending those cuts, which are due to expire in 2010, in order to conform to Republican orthodoxy. And while Obama has long criticized those Bush tax cuts, he too now says that they may be extended because of current conditions. Further tax cuts – and especially tax hikes – are risky propositions.

With the national debt hovering at $9.7 trillion – and expected to top $11 trillion by the time Bush leaves office – the top priority for the new president will be reining in spending. That means no new health care initiatives, no education reform, no Social Security plans. Go up against Iran? We don’t have the money, or the troops.

Which brings us to Iraq. Determined to control his legacy on the issue, Bush is pushing through agreements with the Iraqi government before he leaves office. Prime Minister Nuri al-Maliki has endorsed a withdrawal plan that would have US troops out by 2011.

While Obama may not be able to pull out as quickly as he would like, McCain won’t be able to maintain the open-ended commitment to “victory” he pledges. Whoever wins will need to manage an orderly and relatively rapid withdrawal, and both are likely to leave their supporters disappointed.

Further, both McCain and Obama want to shift our forces to Afghanistan and Pakistan, where they are more urgently needed. As a practical matter, both will need to wind down our Iraq operations just to free up the troops needed elsewhere.

Of course, the next president appoints the Supreme Court. But even there, not much room exists to make an impact.

Thanks to Bush’s Sam Alito and John Roberts appointments, a narrow conservative majority on the High Court is locked in for the foreseeable future. Antonin Scalia, Clarence Thomas and Anthony Kennedy aren’t going anywhere. The best Obama can hope for is to preserve and strengthen the four-seat liberal faction if John Paul Stevens or Ruth Bader Ginsburg retires.

Conversely, McCain would not have much opportunity to turn the court further to the right, if that were his goal. He’d almost certainly face a Congress significantly more Democratic than today’s. Even if his newfound zeal on the right’s pet social issues is genuine, and not just for show, he’d be wise to pick his battles when it comes to nominating judges. A Senate with as many as 60 Democrats, plus several moderate Republicans, is not likely to confirm a Supreme Court nominee who would reverse Roe vs. Wade.

To be sure, the limited options facing the next president don’t mean that the job is unimportant. And previous “mopping up” presidents have gotten some victories under handcuffed circumstances.

Bill Clinton is an example. He campaigned in 1992 on a strong economic program including significant new government spending (or “investments”) in the form of a stimulus package. The ballooning deficit wasn’t his big issue, even though it was a major topic for rivals Paul Tsongas and Ross Perot.

Once elected, Clinton assembled his team of economic advisors, who warned him that he urgently needed to confront the damage the deficit was causing. The bold spending proposals from his campaign had to be scrapped.

As recounted in Bob Woodward’s “The Agenda,” Clinton grumbled that he hadn’t gotten himself elected just to become an “Eisenhower Republican.” Nevertheless, to satisfy the bond markets and build investor confidence, he took the bitter pill and switched his economic agenda to a deficit-reduction program – a mix of tax increases and spending cuts that passed both House and Senate without a single Republican vote.

The shift on economics cost Clinton dearly in political terms. He lost control of Congress the next year (just as George H.W. Bush lost the presidency because he raised taxes to fight the deficit). But Clinton’s program cut out half a trillion dollars in federal debt, allowed the once-untamable budget to be balanced, and arguably set in motion the prosperity of the ’90s. Still, it irked the former president that he didn’t get credit for the economic turnaround, and failed to get many of his pet projects – including health care reform – off the ground.

We are told again and again that this election is the most critical ever. McCain supporters believe Obama’s policies will bring about the apocalypse. Obama supporters say change must come. But don’t believe them: Whoever takes office, it’s four more years of Bush’s legacy, whether they like it or not.

It may help lower the anxiety level on both sides of this election if we take note that the winner is not going to the White House to enact a bold agenda or to change the course of history. Thanks to eight years of colossal mismanagement by George Bush, both Obama and McCain are merely getting measured for a straitjacket.